As multimedia applications become readily available in cellular telephones and other handheld devices such as personal digital assistants and ebooks, the power drain of the devices increases.
This increase in power drain has put a limit on the use of many applications and is one of the challenges facing cellular handset makers. To combat this problem in cellular telephones with monochrome liquid crystal displays, the integration of a solar panel behind a STN display to collect ambient light energy for either emergency or standby uses has been described, for example, in the technical article “Photovoltaic Cell Integrated into an LCD” published by the Society for Information Display in May, 2002 (Society of Information Display Digest of Technical Papers, Vol XXXIII, No. 1, Page 190–193, Authors: Zili Li, P. Desai, D. Voloschenko, and M. Smith). This supplementary power source is an integrated part of the monochrome display. However, the monochrome display is rapidly being replaced by color displays, so there is a need for supplementary power for telephones and other portable devices with color displays.
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